Pulverizing mill



June 11, 1940. P sw TZ 2,204,057

- PULVERIZING MILL Filed June 15, 1937 q r U Patented June 11, 1940 UNITED- STATES PATENT OFFICE 8 Claims.

My invention relates to improvements in mills for finely comminuting and pulverizing materials of various kinds.

Its principal objects are to provide improved means for reducing materials to extremely fine particles without crushing them, and to accomplish this with low power consumption and without undue temperature or exposure to the atmosphere; and to provide adequate means for comminuting finely any material which may be suspended in or conveyed by a liquid, or which though dry, may be pumped or injected into the mill.

Heretofore various grinding mills, which depend on impact, pressure or rubbing have been constructed, but these are expensive to operate and fail to produce a product of uniform fineness. Colloid and similar type mills usually employ a pair of disks with their acting faces in juxtaposition, one of them running and the other standing immovable, or both running in opposite directions in close proximity, either depending on hydraulic shear, or the faces of the disks being provided with shallow grooves or otherwise roughened or ribbed, depending upon the rubbing or crushing action to accomplish the grinding of the material introduced, and requiring thrust bearings to take up the pressure incident thereto.

The mill embodying my invention is otherwise constructed, and accomplishes the reduction of material by frequently cutting it by knifelike edges closely held against each other and moving across each other like numerous pairs of shears or scissors, which cut and recut until the article is finely comminuted to any desired fineness and dropped into a receptacle.

My mill comprises a central disk, having a series of perforated slots, adapted to rotate freely between a pair of non-rotatable and adjustable disks, each provided with a series of radial grooves cut in the face adjacent to the rotatable disk, and equipped with sharp cutting edges.

The radial grooves end a short distance from the periphery in order to provide fiat, nongrooved areas adjacent the periphery as shown in Fig. 3. These grooves may be of equal depth or of unequal depth in which case they taper from the center outwardly to the surface. The

central disk has similar flat, non-grooved areas which co-operate with the peripheral surfaces of the non-rotatable members. The device is adjusted so that the clearance between f these peripheral surfaces is equal to the maximum particle size desired for the treated product.

The material to be comminuted is introduced through the center of one of the non-rotating disks and passes directly into the slots of the rotating disk where it is engaged by the grooves of the non-rotating disks, the sharp cutting edges of both acting thereon as shears or scissors until the material is cut up fine enough to pass between the adjacent peripheral surfaces of the rotating and non-rotating disks and is discharged at the periphery of the rotating disk.

The central disk is movably mounted on a shaft in sucha manner as to permit movement of the disk along the shaft in accordance with the adjustment of the non-rotating disks, and to insure the faces of the rotating and nonrotating disks being at all times parallel. It will be obvious that the mounting of the rotating disk will be sufilciently loose so as to permit free movement in order that the disks, both rotatable and non-rotatable, may be at all times in alignment and with parallel faces.

Rapidity of rotation may be controlled by any suitable gear in connection with the motor in the usual well known way.

The rotating disk is perforated by slots which are out completely through it. The slots extend generally radially of the disk and terminate short of the outer periphery of the disk. The disk may be cut so as to form slots only part way from the center to the periphery and to form grooves in the remaining portion of the disk,that is, from the point where the slots terminate to a point adjacent the periphery, so that the outer portions of the slots are in the form of grooves on each side of the disk separated by a septum.

A stumng box is provided on the shaft to prevent leakage. A suitable housing supports the disks, in connection with means hereinafter more fully described, provides for adjusting and maintaining definite and exact clearance between the disks, and for access thereto for adjustment and cleaning thereof.

My invention is illustrated by the accompanying drawing, in which similar letters indicate like parts.

Referring thereto; Fig. 1 is a side view, partly in section of the entire mill. Fig. 2 is a. preferred detail side view of the central rotating disk; Fig. 3 is a view of the cutting side of one of the nonrotating disks, the other being very similar thereto; Fig. 4 is a section taken along the line 4-4 of Fig. 1. In the drawing, A indicates the central rotating disk; 13 and C the non-rotatable disks; D is the outline of a motor in connection with the drive shaft, E; F, is the hopper through which the material is fed into the comminuting disks.

Y -'I'he hopper is solidly attached to the adjacent non-rotating disk, and may be utilized to regulate the space between the. rotatable and nonrotatable disks, B and C by means of a threaded bolt G which holds the adjacent non-rotating disk firmly and adjustably to maintain the amount of clearancedesired between the disks. A guide bar X, (Fig. 1) and rib Y thereon, aids in holding and guiding the hopper into position.

Other and equivalent means may be provided, and micrometer indication for the purpose, the size of the comminuted particles being governed by the space or clearance between the disks at the periphery where the grooves and slots terl5 minate, a, a, in Fig. 2, indicate the slots in the rotating disk, the cutting edges of which are preferably curved to a degree such that the cutting edges of slots and grooves are at an angle with each other best adapted to shear the mate-, rial gradually delivered to them.

The maximum size of the material which may be fed into theslots is determined by the thickness of the rotating disk and width of the slots,

, and expulsion of the material may be facilitated by pressure thereon through the hopper adapted to impel it outwardly until it passes over the space between the ends of the grooves and slots and the periphery, and the finely comminuted product escapes into a receptacle.

' Inasmuch as my mill utilizes both faces of the rotating disk, no thrust bearings are required, as heretofore, to take up the pressure on the driving shaft. Women the disks does not dull the cutting edges but they are self-sharpening and agperfectly balanced on the shaft, and always parallel to each other,

The central disk may be rotated in either direction thus permitting the sharp edges of both sides of each slot and grooves to be used for cut- 40 hing. Direct access is afforded to the grooves and slots by withdrawing the threaded bolts d, d, which secure the outer disk C to the frame H, to clean the disk, and sliding it outwardly along the shaft E.

45 Other'means may be provided therefor, and

modification made within the scope of the invention. Multiple units may be provided, and the double knife edges double the capacity of the mill. Speed of rotation increases the output .60 of the mill, and assists centrifugal movement of the material therein.

I do not limit my claims to mere matter of form, but broadly claim as follows:

1. In a cutting or shearing device, the combi- 55 nation with a housing frame, of a pair of nonrotating disks mounted thereon, spaced apart a limited distance, a series of radial sharp-edged grooves cut in the adjacent face of each disk from the center to near the periphery, flat un- 60 grooved areas between the ends of the grooves and the periphery, an intermediate disk rotatable between the pair of non-rotatable disks in close proximity thereto, said disk having a series of sharp-edged slots perforated therethru, and hav- 65 ing flat, unslotted areas adjacent its periphery adapted and arranged to coact with the fiat, ungrooved areas of said non-rotating disks, means for delivering material into the slots at the center of the rotating disk, and means for adjusting 70 and maintaining proper clearance between the rotating and non-rotating disks, and for rotating the central disk.

2. In a cutting or shearing device, the combination with a housing frame, of a pair of non- 75 rotating disks mounted thereon, spaced apart a limited distance, a series of radial sharp-edged .grooves cut in the adjacent face of each disk.

and terminating short of the periphery, an intermediate disk rotatable between the pair of nonrotating' disks in close proximity thereto such 8 disk having a series of slots perforated therethru,

and a series of radial grooves out in both faces from the slots to near the periphery, both slots and grooves being faced with sharp edges, means for delivering materialinto the slots at the cenl0 ter of the rotating disk and means for adjusting and maintaining proper clearance between the rotating and non-rotating disks, and for rotating the central disk.

3. Ina cutting mill, in combination with a 15 housing frame, a pair of non-rotating disks, an intermediate disk rotatable between them parallel therewith, means, including opposed flat surfaces at the periphery of each disk arranged in close proximity to each other, a series of ra- 0 dial. groves in each non-rotating disk, and a series of slots perforated through the intermediate disk, the grooves equipped with, sharp edges and the slots equipped with sharp edges fitted to engage the sharp edges of both non-rotating 25 disks as shears or scissors to comminute the materials between them, and means for adjusting and maintaining proper clearance between the disks, and means for access thereto for-cleansing.

4. In a cutting or shearing mill for finely com- 30 minuting material, the combination with an enclosed casing, a pairof radially grooved non-rotatable surfaces mounted in said casing in spaced parallel relationship, a slotted disk rotatably mounted between said surfaces, the slots and grooves terminating short of the peripheries of said disks to provide flat surfaces on said disks in close proximity to each other, said slots and grooves being in shearing relationship with each other, means for feeding material into the slots at the center of said disk and means for rotating the same.

5. In a cutting or shearing mill for finely comminuting material, the combination with an enclosed casing, a pair of radially grooved non-rotatable surfaces mounted in said casing in spaced parallel relationship, a slotted disk rotatably mounted between said surfaces, the slots and grooves terminating short of the peripheries of said disks to provide flat surfaces on said disks in close proximity to each other, said slots and grooves being in shearing relationship with each other, means for regulating the clearance between the disk and the non-rotatable surfaces,

means for feeding material into the slots of said disk and means for rotating the same.

6. In combination with a cutting device, a rotatable perforated disk mounted in shearing relationship with a pair of non-rotatable radially grooved members, flat areas on the periphery of 0' the disk and said members in close proximity to each other, means for feeding material to the perforations of said disk and means for rotating said disk.

7. In combination with a cutting device, a rotatable perforated disk mounted in shearing relationship with a pair of non-rotatable radially grooved members, coacting flat areas adjacent the periphery of said disk and said members, an opening through the center of one of said nonrotatable members through which material may be fed to the perforations of said disk, and means for rotating said disk.

8. In a cutting or shearing device, the combination with a housing frame of a pair of sta- 7 tionary disks mounted thereon, spaced apart a limited distance, provided with cutting edges radially disposed in the opposed faces of each disk and extending from the center of said disks to a point short of the periphery thereof, a rotatable disk positioned between said stationary disks, said rotatable disk being perforated by slots having cutting edges on both sides of said rotatable disk capable of cutting when said disk between the rotatable disk and the stationary 5 disks and means for rotating the rotatable disk in either direction.

PAUL SWARTZ. 

